No need to apologise, thanks for asking, I didn't explain that part in much depth, and you've inspired me to add some links to tutorials.
render_cameras.py and toon_shader_process.py are run inside Blender, as Blender python scripts. Here's a tutorial which goes into running python in Blender: https://www.lowpolymodelsworld.com/post/blender-scripting-for-beginners-a-step-b...
combine fotosketcher.py is run on your computer as a stand alone python script. The specific steps to run it will depend on your computer. Here's a tutorial about running it on windows I found by searching for "Run python Windows", there are similar tutorials out there for Mac and Linux. https://learnpython.com/blog/run-python-script-windows/ I personally run python on a Mac laptop via Visual Studio Code's inbuilt terminal.
I only skimmed these tutorials to make sure they seemed basically okay, but if they don't work for you there's lots of others out there.